Crosslinked polymers prepared from allyl or methallyl-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid imides and bisimides

ABSTRACT

Crosslinked polymers with excellent physical properties are prepared by heating at 180 DEG -300 DEG  C. the imides of the formula I &lt;IMAGE&gt;  (I)  in which E is allyl or methallyl, R is hydrogen, alkyl, alkenyl, cycloalkyl, aryl or benzyl when n is 1, and R is alkylene or arylene when n is 2. The polymers can be used, in particular, for the preparation of glass fiber-reinforced and carbon fibre-reinforced plastics and as electrical insulating materials.

This is a divisional of application Ser. No. 517,096, filed July 25,1983, now U.S. Pat. No. 4,515,962, issued on May 7, 1985.

The invention relates to bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidimides substituted by allyl or methallyl, their preparation and thepolymers obtainable therefrom by heating.

Maleimides and bismaleimides, as well as N-allylmonomaleimides areknown.

U.S. Pat. No. 3,334,075 describes the curing of halogenated olefinicrubber polymers with selected polymaleimide compounds, such asN,N'-m-phenylene-bismaleimide. These polymaleimides contain no allyl ornorbornenyl groups.

British Pat. No. 1,277,790 describes resin-forming compositionscontaining maleimide or bismaleimide derivatives, such asN-phenylmaleimide and methylene-bis-(N-phenylmaleimide). None of thesecompounds contains norbornenyl or allyl groups.

U.S. Pat. No. 3,839,358 describes a process for the preparation ofbismaleimides by reacting a bismaleamic acid with the anhydride of a lowmolecular weight carboxylic acid in the presence of a tertiary amine, anorganic solvent and a nickel catalyst. U.S. Pat. No. 4,229,351 describesa process for the preparation of mono- and bis-maleimides containingaliphatic substituents on the nitrogen atom. The preparation ofcompounds with allyl-substituted norbornenyl groups is neither describednor suggested in either one or the other patent.

U.S. Pat. No. 3,450,711 relates to bisimide compounds which are preparedby reacting endo,cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidanhydride (=5-norbornene-2,3-dicarboxylic acid anhydride) with selectedorganic diamines. These bisimides contain no allyl substituents anddiffer from the present compounds both in respect of their structure andin respect of their chemical reactivity. The compounds according to thisU.S. patent are used as intermediates in the preparation of epoxidecompounds.

It is also known that polyimide oligomers can be prepared by an additionreaction between 3,3',4,4'-benzophenonetetracarboxylic acid dianhydrideand diaminodiphenylmethane in the presence of various compounds capableof crosslinking and masking end groups, such as unsubstituted orchlorinated 5-norbornenecarboxylic acid anhydride and 5-vinylphthalicacid anhydride, these oligomers being used as adhesives [cf., forexample, Polym, Eng. Sci., 22, 9-14 (1982)]. These polyimide oligomerscontain no allyl groups.

U.S. Pat. No. 4,271,074 describes silanes prepared from imideintermediates, for example N-allyl-2,3-dimethylmaleimide. The monomersaccording to the invention have a norbornenyl group substituted by anallyl group, and are therefore structurally quite different and are notsuggested by this patent.

The preparation of the starting substances for the compounds accordingto the invention is described in U.S. Pat. No. 3,105,839.

The allyl- or methallyl-substitutedbicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid imides according to theinvention are useful starting substances for polymers of excellentproperties. They have the following formula I: ##STR2## in which E isallyl or methallyl, n is 1 or 2 and, if n is 1, R is hydrogen, alkylhaving 1-12 C atoms, alkenyl having 3-6 C atoms, cycloalkyl having 5-8 Catoms, aryl having 6-10 C atoms or benzyl or, if n is 2, R is --C_(m)H_(2m) --, in which m=2-20, arylene having 6-10 C atoms or a group ofthe formula II ##STR3## in which T is methylene, isopropylidene, CO, O,S or SO₂.

E is preferably the allyl group.

R can be a straight-chain or branched alkyl group having 1-12 C atoms,such as methyl, ethyl, isopropyl, n-butyl, isopentyl, n-hexyl,2-ethyl-hexyl, n-decyl or n-dodecyl, and is preferably alkyl having 1-8C atoms.

R can also be a straight-chain or branched alkenyl group having 3-6 Catoms, such as allyl, methallyl, 2-butenyl and 3-hexenyl, preferablyallyl.

A cycloalkyl group R can be a cyclopentyl, cyclohexyl, cycloheptyl orcyclooctyl group, preferably cyclohexyl.

An aryl group R can be unsubstituted phenyl or a phenyl group which issubstituted by one or two methyl groups, such as tolyl or xylyl, ornaphthyl. The phenyl group is preferred. A --C_(m) H_(2m) -- group R canbe a straight-chain or branched radical, such as ethylene, propylene,trimethylene, tetramethylene, hexamethylene, octamethylene ordodecamethylene. A group R of the formula II is preferably bonded to theN atoms in the 4,4'-positions.

R is preferably a --(CH₂)_(m) -- group, in which m=2 to 12.

An arylene group R having 6-10 C atoms is, for example, a m-phenylene,p-phenylene, 1,3-naphthylene, 1,4-naphthylene or 1,5-naphthylene group.

In a group R of the formula II, T is preferably the methylene group, Oor SO₂.

Preferred compounds of the formula I are those in which E is allyl and,if n is 1, R is hydrogen, alkyl having 1-8 C atoms, allyl, cyclohexyl,phenyl or benzyl, or, if n is 2, R is --(CH₂)_(m) --, in which m=2-12,m- or p-phenylene or a group of the formula II, in which T is themethylene group, O or SO₂.

Particularly preferred compounds of the formula I are those in which Eis the allyl group, n is the number 2 and R is --(CH₂)₂ --, --(CH₂)₆ --or ##STR4## or, in particular, ##STR5##

The imides according to the invention can be prepared in a manner whichis known per se, for example by reacting an anhydride of the formula III##STR6## with a compound of the formula IV ##STR7## in which E, R and nare as defined under formula I, at elevated temperature, the waterformed during the reaction being distilled off. If the compounds of theformula IV are ammonia or a low-boiling monoamine, an excess of thesereactants is recommended. Diamines are advantageously to be used in astoichiometric ratio. The reaction can be carried out without a solventor in the presence of an inert solvent, which can be used for azeotropicremoval of the water (entrainer). The temperature of the reaction can bebetween 100° and 250° C. The imides of the formula I are preferablyprepared in the melt under a pressure of at most 4,500 Pa attemperatures between 130° and 220° C., in particular 180° and 220° C.

As already mentioned, the starting substances of the formula III can beprepared by the process described in U.S. Pat. No. 3,105,839 by reactionof sodium cyclopentadienide with an allyl or methallyl halide, followedby a Diels-Alder reaction with maleic anhydride. Although the U.S.patent specification states that the allyl group is bonded in the7-position of the bicyclic system, more recent investigations show thatan isomer mixture in respect of the position of the allyl group and alsoin respect of the endo- and exo-configuration of the anhydride moiety isformed. It has not yet been possible to isolate the isomeric componentsby conventional methods of separation.

The monoamines or diamines used of the formula IV are known, or they canbe prepared by processes which are known per se.

The compounds according to the invention are liquid or low-melting solidsubstances which can be polymerised to solid products with a high glasstransition temperature and stability to heat and water. These productscan be used in many ways, for example as casting resins or adhesives,and in particular for the production of glass fiber-reinforced or carbonfiber-reinforced plastics, and as electrical insulating materials.

The compounds according to the invention can be used and polymeriseddirectly, or they can first be dissolved in an organic solvent, such astoluene, xylene, methyl ethyl, ketone, an ethylene glycol monoalkyl ordialkyl ether having 1-4 C atoms in the alkyl groups or a similarsolvent conventional in the coatings industry. Such solutions can beused as impregnating agents or coating agents, or they can be dispatchedto the consumer.

The invention also relates to the novel polymers which can be obtainedby heating an imide of the formula I at a temperature between 180° and300° C., preferably between 200° and 250° C., for 6 to 24 hours. Theabove statements apply in respect of preferred definitions of E, R andn, Particularly preferred polymers are those which can be obtained byheating an imide of the formula I in which E is the allyl group, n isthe number 2 and R is the group ##STR8## at 240° to 250° C. for 6-12hours. No catalysts which substantially accelerate the polymerisationhave yet been found.

Inert and stable substances, such as fillers, pigments, dyes and otheradditives, can, of course, be added to the imides of the formula Ibefore they are polymerised to crosslinked structures.

EXAMPLE 1 Preparation of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylicacid imide.

A mixture of 102 g of allyl-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylicacid anhydride, prepared according to Example 1 in U.S. Pat. No.3,105,839, and 68.1 g of 25% aqueous ammonia solution is refluxed withcooling at 95°-102° C. for 70 minutes, while stirring. The water andexcess ammonia are then distilled off under reduced pressure (6,133 Pa).When the internal temperature reaches 120° C., 54 ml of aqueous ammoniahave been distilled off. An orange-coloured, viscous residue remains,and is distilled under a pressure of 13.3 Pa. 62.07 g ofallyl-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid imide pass overbetween 132° and 135° C., corresponding to a yield of 60% of theory. Theimide is a yellow oil of refractive index n_(D) ²⁰ 1.5421 and viscosityη₂₅ 345 Pa.s at 25° C.

    ______________________________________                                        Analysis         % C       % H    % N                                         ______________________________________                                        calculated for C.sub.12 H.sub.13 NO.sub.2 :                                                    70.9      6.45   6.90                                        found:           70.7      6.6    6.9                                         ______________________________________                                    

IR spectrum: 1,620 cm⁻¹ cyclic double bond; 1,640 cm⁻¹ allyl group;1,725 cm⁻¹ carbonyl group; 1,772 cm⁻¹ carbonyl in the cyclic imide; and3,390 cm⁻¹ NH vibration.

After polymerisation at 240° C. for 24 hours, a solid substance with aglass transition temperature of 218.5° C. is obtained. It no longer hasthe IR absorption frequencies at 1,620 and 1,640 cm⁻¹ characteristics ofdouble bonds.

EXAMPLE 2 Allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidN-methylimide.

A mixture of 204 g of the anhydride used in Example 1 and 113 g of a 33percent by weight solution of methylamine in alcohol is refluxed withcooling at 65° C., while stirring. An exothermic reaction occurs at thistemperature. The mixture is cooled somewhat and warmed at 60°-65° C. fora further 2.5 hours and the alcohol, excess methylamine and a littlewater are distilled off (111 ml). When the internal temperature reaches165° C., the pressure is reduced in steps to 6,665 Pa and the mixture iskept under these conditions for 30 minutes.

Distillation of the red-brown crude product gives, at 104°-110° C. under12 Pa, 165.62 g (76% of theory) of a yellow oil of n_(D) ²⁰ 1.5269 andη₂₅ =1 Pa.s.

    ______________________________________                                        Analysis:        % C.      % H    % N                                         ______________________________________                                        calculated for C.sub.13 H.sub.15 NO.sub.2 :                                                    71.87     6.96   6.45                                        found:           72        7.0    6.6                                         ______________________________________                                    

Polymerisation at 240° C. for 24 hours gives a solid substance which hasa glass transition temperature (GTT) of 218.5° C. and shows no C═Cabsorption frequency at 1,620 and 1,640 cm⁻¹ in the IR spectrum.

EXAMPLE 3 Allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidN-allylimide.

377.6 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidanhydride are mixed with 131.9 g of allylamine and the mixture isheated, using a descending condenser, until the internal temperaturereaches 175° C. 59 ml of distillate (water and excess allylamine) areobtained. On distillation, 399.32 g (88.7% of theory) of a light yellowoil of n_(D) ²⁰ 1.5272 and η₂₅ 0.69 Pa.s are obtained at between 120°and 123° C. under 40 Pa.

    ______________________________________                                        Analysis:        % C       % H    % N                                         ______________________________________                                        calculated for C.sub.15 H.sub.17 NO.sub.2 :                                                    74.05     7.05   5.76                                        found:           74.2      7.1    5.8                                         ______________________________________                                    

Polymerisation at 240° C. for 24 hours gives a solid substance with aGTT >290° C. No C═C absorption frequencies can be detected at 1,620 and1,640 cm⁻¹ in the IR spectrum.

EXAMPLE 4 Allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidN-(2-ethyl-hexyl)-imide.

The procedure described in Example 3 is repeated, except that 204 g ofallyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride and 129 gof 2-ethylhexylamine are used. 17 g of water are split off ayt 115° to160° C. under 4,000 Pa in the course of 4.5 hours. 292.05 g (92.6% oftheory) of a fraction of boiling point 160°-164° C. under 10.7 Pa, n_(D)²⁰ 1.5038 and η₂₅ 0.68 Pa.s are obtained.

    ______________________________________                                        Analysis         % C       % H    % N                                         ______________________________________                                        calculated for C.sub.20 H.sub.29 NO.sub.2 :                                                    76.15     9.27   4.44                                        found:           76.2      9.4    4.4                                         ______________________________________                                    

EXAMPLE 5 Allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidN-cyclohexylimide.

102 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydrideand 100 g of cyclohexylamine are heated to 137° C. under 4,000 Pa. 59 mlof water and excess cyclohexylamine are distilled off. Distillation ofthe residue at 162°-163° C. under 10.7 Pa gives 87.6 g (62% of theory)of an oil of n_(D) ²⁰ 1.5296 and η₂₅ 72.8 Pa.s.

    ______________________________________                                        Analysis:        % C       % H    % N                                         ______________________________________                                        calculated for C.sub.18 H.sub.23 NO.sub.2 :                                                    75.8      8.07   4.91                                        found:           75.5      7.95   4.95                                        ______________________________________                                    

EXAMPLE 6 Allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidN-phenylimide.

93 g of aniline are added dropwise to 102 g ofallyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydride, whilestirring. During this addition, the temperature rises to 80° C. Themixture is heated to 150° C. and the pressure is reduced to 4,266 Pa. 9ml of water and 46 ml of aniline distil off. Distillation gives 82.37 g(60% of theory) of a viscous yellow oil of boiling point 183° C. under12 Pa, n_(D) ²⁰ 1.5738 and η₂₅ 105.6 Pa.s.

    ______________________________________                                        Analysis:        % C       % H    % N                                         ______________________________________                                        calculated for C.sub.18 H.sub.17 NO.sub.2 :                                                    77.4      6.14   5.02                                        found:           77.2      6.4    5.02                                        ______________________________________                                    

Polymerisation at 240° C. for 24 hours gives a solid substance with aGTT of 230° C. No absorption frequencies for ##STR9## are found in theIR spectrum (1,620 and 1,640 cm⁻¹).

EXAMPLE 7 Allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidN-benzylimide.

102 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydrideand 85.6 g of benzylamine are boiled under reflux for 2 hours. Water andexcess benzylamine are then distilled off (39 ml at 105° C. under 4,132Pa).

Distillation at a boiling point of 170°-184° C. under 10.7 Pa gives117.35 g (80% of theory) of a yellow oil of n_(D) ²⁰ 1.5612 and η₂₅ 17.3Pa.s.

    ______________________________________                                        Analysis:        % C       % H    % N                                         ______________________________________                                        calculated for C.sub.19 H.sub.19 NO.sub.2 :                                                    77.79     6.53   4.87                                        found:           77.5      6.7    5.1                                         ______________________________________                                    

EXAMPLE 8N,N'-Ethylene-bis-(allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidimide).

204 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydrideare taken and 30 g of ethylenediamine are added dropwise, whilestirring. The temperature rises to 130° C. The temperature is increasedto 180° C.; during this procedure, 14 ml of water distil off. Themixture is then heated at 200° C. under a pressure of 9.3 Pa for afurther 2 hours. 210 g of a yellow resin which is solid at roomtemperature and has a softening point of 56° C., measured on a Koflerhot bench, are obtained. Molecular weight (number-average) M_(n) =504,(weight-average) M_(w) =1,204, determined by the gel permeationchromatography method.

    ______________________________________                                        Analysis:         % C        % H   % N                                        ______________________________________                                        calculated for C.sub.26 H.sub.28 N.sub.2 O.sub.4 :                                              72.20     6.53   6.48                                       found:            71.7      6.5    6.4                                        ______________________________________                                    

After polymerisation at 240° C. for 12 hours, a solid substance with aglass transition temperature of 354° C. is obtained.

EXAMPLE 9N,N'-Hexamethylene-bis-(allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylicacid imide).

A mixture of 204 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylicacid anhydride and 58 g of hexamethylenediamine is heated, over thecourse of 3 hours, to 175° C., with a descending condenser, whilestirring. The pressure is then reduced to 1,866 Pa and the mixture isstirred at 175° C. for a further hour. 235 g of an amber-coloured resinwhich is just still liquid at room temperature are obtained.

    ______________________________________                                        Analysis:       % C    % H     % N                                            ______________________________________                                        calculated for C.sub.30 H.sub.36 N.sub.2 O.sub.4 :                                            73.74  7.43    5.73 --M.sub.n = 560                           found:          73.4   7.4     5.5  --M.sub.w = 1,173                         ______________________________________                                    

EXAMPLE 10N,N'-Dodecamethylene-bis-(allyl-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylicacid imide).

100.66 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acidanhydride and 49.34 g of 1,12-diaminododecane are heated gradually at200° C., finally in vacuo. 140 g of a viscous, amber-coloured resin areobtained.

    ______________________________________                                        Analysis:         % C       % H    % N                                        ______________________________________                                        calculated for C.sub.36 H.sub.50 O.sub.4 N.sub.2 :                                              75.22     8.77   4.87                                       found:            75.8      8.75   5.1                                        ______________________________________                                    

EXAMPLE 11Bis-[4-(Allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboximidophenyl)-methane].##STR10##

204 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydrideand 99 g of 4,4'-diaminodiphenylmethane are heated to 200° C. in vacuoand kept under these conditions for 1 hour. 280 g of a brown solid resinwith a softening point of 104° C., a viscosity of 0.425 Pa.s at 200° C.and an acid number of 0 are obtained.

    ______________________________________                                        Analysis:       % C    % H     % N                                            ______________________________________                                        calculated for C.sub.37 H.sub.34 N.sub.2 O.sub.4 :                                            77.87  6.01    4.91 --M.sub.n = 977                           found:          78.2   6.1     5.0  --M.sub.w = 4,718                         ______________________________________                                    

EXAMPLE 12 218 g of methallyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylicacid anhydride (boiling point=139°-142° C. under 20 Pa) and 99 g of4,4'-diaminodiphenylmethane are heated to 200° C. in vacuo and kept atthis temperature for 1 hour. 295 g of a brown solid resin with asoftening point of 98° C. and an acid number of 2 mg of KOH/g areobtained.

    ______________________________________                                        Analysis:         % C       % H    % N                                        ______________________________________                                        calculated for C.sub.38 H.sub.36 N.sub.2 O.sub.4 :                                              78.04     6.12   4.79                                       found:            78.3      6.1    4.8                                        ______________________________________                                    

EXAMPLE 13 ##STR11##

204 g of allyl-bicyclo[2.2.1]-hept-5-ene-2,3-dicarboxylic acid anhydrideand 54.0 g of 1,4-phenylenediamine are heated at 220° C. under 2,000 Pa,the water of reaction being distilled off. 228 g (95% of theory) of adark brown solid resin with a softening point of 140° C. are obtained.

    ______________________________________                                        Analysis:         % C       % H    % N                                        ______________________________________                                        calculated for C.sub.30 H.sub.28 N.sub.2 O.sub.4 :                                              74.98     5.87   5.83                                       found:            74.7      6.1    6.1                                        ______________________________________                                    

EXAMPLE 14 ##STR12##

408 g of allyl-bicyclo[2.2.1hept-5-ene-2,3-dicarboxylic acid anhydrideand 204.3 g of 4,4'-diaminodiphenyl ether (melting point=188°-190° C.,decomposition, 98% pure) are heated to 200° C. 35 cm³ of water therebydistil off. The pressure is reduced to 40 Pa, the mixture is heated to220° C. and this temperature is maintained for one hour. 555.8 g of adark brown solid resin (96.5% of theory) with a softening point of 142°C. are obtained.

    ______________________________________                                        Analysis:         % C      % H    % N                                         ______________________________________                                        calculated for C.sub.36 H.sub.32 N.sub.2 O.sub.5 :                                              75.51    5.63   4.89%                                       found:            75.5     5.7    4.9                                         ______________________________________                                    

EXAMPLE 15 ##STR13##

102 g of allyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid anhydrideand 62 g of 4,4'-diaminodiphenyl sulfone (melting point=174°-176° C.)are heated to 180° C., the pressure is reduced to 27 Pa and the mixtureis kept under these conditions for 1 hour. 135.6 g of a brown solidresin (87.5% of theory) with a softening point of 108° C. are obtained.

PREPARATION OF CROSSLINKED POLYMERS

The compounds according to the invention have two or more olefinicdouble bonds in the molecule which are capable of polymerisation. Onheating, crosslinked polymers with useful physical properties areobtained.

USE EXAMPLES EXAMPLE I

The resin prepared according to Example 8 is poured as a mobile meltinto a 12×12×0.4 cm³ steel mould pre-heated to 200° C. and is cured at200° C. for 12 hours and at 240° C. for 12 hours. After cooling, thesheet is cut into test bars. The following properties are determined onthese bars:

    ______________________________________                                        Flexural strength acording to DIN 53,452:                                                             95.4 N/mm.sup.2                                       Flexural impact strength according to                                                                 7.54 kJ/m.sup.2                                       DIN 53,455:                                                                   Absorption of water in 1 hour at 100° C.:                                                      0.25% by weight                                       Vicat softening point according to                                                                    >250° C.                                       DIN 53,460:                                                                   Weight loss after 30 days at 250° C.                                                           2.23% by weight                                       in air:                                                                       ______________________________________                                    

Sticking of metal: Anticorodal B metal strips (170×25 mm²) are stuck,with an overlap of 12.5 mm, with the resin melt from Example 8 and themelt is cured as described above. The tensile strength according to DIN53,283 is 5.7 N/mm².

EXAMPLE II

The imide prepared according to Example 9 is poured as a hot, mobileresin into a 12×12×0.4 cm³ steel mould and is cured at 200° C. for 1hour, at 220° C. for 1 hour and at 240° C. for 12 hours. After cooling,test bars are cut out of the sheet. The following properties aremeasured on these bars:

    ______________________________________                                        Flexural strength according to DIN 53,452:                                                            89.8 N/mm.sup.2                                       Deflection:             4.3 mm                                                Flexural impact strength according to                                                                 9.2 kJ/m.sup.2                                        DIN 53,455:                                                                   Vicat softening point according to                                                                    247° C.                                        DIN 53,460:                                                                   Absorption of water (1 hour at 100° C.):                                                       0.42% by weight                                       Tensile strength on Anticorodal                                                                       7.2 N/mm.sup.2                                        according to DIN 53,283:                                                      ______________________________________                                    

EXAMPLE III

The imide prepared according to Example 10 is poured into a 12×12×0.4cm³ steel mould and is cured at 220° C. for 15 hours and at 240° C. for4 hours. Test bars from the resulting sheet have the followingproperties:

    ______________________________________                                        Flexural strength:      89.7 N/mm.sup.2                                       Deflection:             6.1 mm                                                Impact strength:        14.4 kJ/m.sup.2                                       Vicat softening point:  152° C.                                        Absorption of water (1 hour at 100° C.):                                                       0.43% by weight                                       ______________________________________                                    

When sheet aluminium is stuck under the same hardening conditions, thetwo sheets to be stuck overlapping by 25×12 mm², an excellent tensilestrength of 10±0.5 N/mm² is obtained according to DIN 53,283.

EXAMPLE IV

The casting resin prepared according to Example 11 is poured into a12×12×0.4 cm³ steel mould and is cured at 220° C. for 6 hours and at240° C. for 14 hours. Test bars have the following properties:

    ______________________________________                                        Flexural strength:      103.1 N/mm.sup.2                                      Deflection:             2.3 mm                                                Impact strength:        12.5 kJ/m.sup.2                                       Vicat softening point:  >260° C.                                       Absorption of water (1 hour at 100° C.):                                                       0.27% by weight                                       Tensile strength on Anticorodal                                                                       5.3 N/mm.sup.2                                        according to DIN 53,283:                                                      ______________________________________                                    

Stability To Heat

Thermal analysis in air at a heating rate of 2° C./minute:

Start of decomposition at 390° C., 10% weight loss at 420° C.

Weight loss after 30 days at 250° C.: 2.4% by weight

Weight loss after 30 days at 275° C.: 3.8% by weight

Flexural strength after 30 days at 250° C.: 104.9 N/m²

Flexural strength after 30 days at 275° C.: 68.5 N/mm²

DIELECTRIC PROPERTIES

Dielectric constant ε at 22° C.: 3.3

Dielectric constant ε at 250° C.: 2.9

Dielectric loss factor according to DIN 53,483 at 22° C.: 0.16%

Dieletric loss factor according to DIN 53,483 at 250° C.: 0.42%

Specific volume resistivity according to DIN 53,482 at 22° C.: 2.8×10¹⁶ohm.cm

Specific volume resistivity according to DIN 53,482 at 250° C.: 1.3×10¹³ohm.cm.

EXAMPLE V

The imide resin prepared according to Example 14 is cast and cured asdescribed in the preceding example. Test bars have the followingproperties:

    ______________________________________                                        Flexural strength:      99.3 N/mm.sup.2                                       Deflection:             3.1 mm                                                Flexural impact strength:                                                                             12.9 kj/m.sup.2                                       Vicat softening point:  >260° C.                                       Weight loss after 30 days at 275° C.:                                                          3.89% by weight                                       Absorption of water (1 hour at 100° C.):                                                       0.55% by weight                                       Tensile strength on Anticorodal                                                                       6.2 N/mm.sup.2                                        according to DIN 53,283:                                                      ______________________________________                                    

What is claimed is:
 1. A polymer, which is obtained by heating an imideof formula I ##STR14## in which E is allyl or methallyl, n is 1 or 2and, when n is 1, R is hydrogen, alkyl having 1-12 C atoms, alkenylhaving 3-6 atoms, cycloalkyl having 5-8 C atoms, phenyl, tolyl, xylyl ornaphthyl, or benzyl or, when n is 2, R is --C_(m) H_(2m) --, in which mis an integer of 2-20, m-phenylene, p-phenylene, 1,3-naphthylene,1,4-naphthylene or 1,5-naphthylene or a group of the formula II##STR15## in which T is methylene, isopropylidene, CO, O, S or SO₂, at atemperature between 180° and 300° C. for 6 to 24 hours.
 2. A polymeraccording to claim 1 where in the imide of formula I E is allyl.
 3. Apolymer according to claim 1 where in the imide of formula IE is theallyl group and, when n is 1, R is hydrogen, alkyl having 1-8 C atoms,allyl, cyclohexyl, phenyl or benzyl, or, when n is 2, R is --(CH₂)_(m)--, in which m is an integer of 2-12, m- or p-phenylene or a group ofthe formula II ##STR16## in which T is the methylene group, O or SO₂. 4.A polymer according to claim 1 where in the imide of formula IE is theallyl group, n is the number 2 and R is --(CH₂)₂ --, --(CH₂)₆ -- or##STR17##
 5. A polymer according to claim 1 where the imide of formula Iis ##STR18##
 6. A polymer according to claim 1 where the imide offormula I is ##STR19##
 7. A polymer according to claim 1 where the imideof formula I is ##STR20##
 8. A polymer according to claim 1 which isobtained by heating an imide of formula I where E is allyl, n is 2 and Ris ##STR21## at a temperature of 240° to 250° C. for 6 to 12 hours.